Line-dividing drafting instrument



Jan. 21, 1964 R. D. MESA LINE-DIVIDING DRAFTING INSTRUMENT Filed July 16, 1962 INVENTOR. Qz'cbarcz .0. Mesa WeAsZZT WM United States Patent M 3,118,233 LLWE-DZVIDING DRAFI h IG WSTRUBTENT Richard 1). Mesa, 937 W. Harding Way, Stockton, Calif. Filed July 16, 1962, Ser. No, $99,970 6 Claims. (Cl. 33-492) This invention relates to drafting instruments, and particularly to one designed to aid the draftsman in dividing a straight line, or the right-angle distance between two parallel lines, into any desired number of equal parts.

The major object of the invention is to provide an instrument for the purpose by means of which the draftsman can easily and quickly divide a line of any length, within the range of the instrument, into any desired number of even parts. Particularly, the instrument enables such parts to be odd divisions of the total length of the line or distance being divided, such as cannot be obtained by the use of scales as ordinarily divided, and which without my improved instrumentfrequently require lengthy try-and-fit manipulations of a compass-type divider to obtain.

It is also an object of the invention to provide a linedividirig drafting instrument which is designed for ease and economy of manufacture.

A further object of the invention is to provide a practical, reliable, and durable line-dividing drafting instrument, and one which will be exceedingly effective for the purpose for which it is designed.

These objects are accomplished by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings:

F IG. 1 is a perspective view of the instrument.

- IG. 2 is a plan view of the instrument as in operation.

FIG. 3 is an enlarged fragmentary cross section of the instrument, taken on line 33 of FIG. 2.

FIG. 4 is a fragmentary end elevation of the instrument, partly broken out and in section.

Referring now more particularly to the drawings and to the characters of reference marked thereon, the instrument comprises a pair of spaced upstanding end supports 1 and 2, of a width at the bottom to rest flatly and in a stable manner on a drafting board or table. The supports are connected adjacent but short of the bottom thereof by a rigid longitudinal bar 3, whose width extends transversely of the supports, as shown.

Exten ing between the supports 1 and 2 for the full distance therebetween above and spaced from the bar 3 is a drum 4, which is turnably mounted on said supports by suitable means, such as end spindles 5 and 6 in the supports 1 and 2, respectively; the latter spindle, beyond or outwardly of the adjacent support 2, being connected to said spindle by a knurled knob '7 whereby the drum may be readily rotated by the operator. The drum 4, which may be of circular form, as shown, or of a multi-sided periphery, is provided with a plurality of peripherally spaced, longitudinally extend ng, full-length scales 8 impri ed thereon, each scale being divided into a nurnber or equal length subdivisions, the subdivisions of the vari us scales being all of difierent lengths relative to each other, as generally indicated; the divisions of the scales reading from the starting or zero mark at the upper end of the instrument, considering the support 1 as being at said upper end.

Slidably supported by the bar 3 for movement along the same from adjacent the support 2 toward the upper end of the instrument is a block 9, which clears the drum 4 and the lower edge of which is slightly above the bottom of the supports, so as not to drag on the table on which the instrument is resting. On its front side the block extends upwardly to a point level with the transverse axial plane of the drum 4, as clearly shown in FIG.

3,,lldi333 Patented Jan. 21, 1%34 3; the front face ltl of the block being disposed at a downward and outward angle to its lower end, and such face being provided with a line or marker 11 disposed at right angles to the axis of the drum and adapted to register with any or" the scale divisions of the drum.

Projecting forwardly from the block at the bottom or lower edge thereof is an elongated straight-edge 12, which extends at right angles to the axis of the drum, and is providedfor substantially its full length-with a slot 13. This slot is alined with the marker 11 on the block face 10, and is of a width sufficient to enable the point of a pencil to be projected therethrough for contact with a drawing mounted on the table or board on which the instrtunent is supported.

In order to control the movement of the block 9 along the bar 3, on which said block has a somewhat snug fit, a knurled friction wheel 14 is mounted on a vertical spindle 15 supported in the block 9 back of the bar 3; said wheel frietionally engaging the back edge of the bar and also projecting from the back face of the block for finger engagement, as clearly shown in FIG. 3.

A similar block 16 is independently slidably mounted on the bar 3 for movement therealong from adjacent the support 1 toward the lower end of the instrument. The front face of this block 16, which also is sloping, is provided with a line or marker 17 to aline with any of the scale divisions, and disposed at right angles to the axis of the drum 4. A short but sharp pin is is mounted in the block 16 at the front thereof and a short distance in front of the drum, as shown in FIG. 3; this pin being alined with the marker 17.

The lower end support 2 is also provided with a paperpenetrating pin 19, but this pin is initially retracted relative to the paper or table, being secured on the lower end of a vertical bar 23 which is mounted for limited vertical movement on the back side of the support 2, said bar 24} having a finger Zl on its upper end projecting laterally out therefrom for easy manual manipulation.

In operation, let it be assumed that it is. desired to divide the space between two lines 2.2 (such as elevation lines on a surveyors drawing) into seven equal parts. First a line 23 is marked on the drawing in intersecting relation to the lines 22. and at right angles thereto. The drum 4- is then adjusted to dispose the scale to be used in a central forwardly projecting position, the scale chosen being the one which will give the desired number of seal divisions in a length of the scale shorter, but not too much shorter, than the actual full length or" the line 2.3 between the lines 22. The block 16 is then adjusted if necessary to dispose the marker 17 in line with the zero mark on the scale, or with a scale division adjacent said Zero mark. The block is then adjusted along the bar 3 and drum 4 so as to dispose the marker ill on said block against the scale mark seven divisions from the mark thereon which is alined with the marker 17 on the block 16.

The instrument is placed on the drawing and the pin 18 is then pressed into the drawing at the exact point of intersection of the upper line 22 with the crossing line 23, as shown. The instrument is then swung about the pin 13 as an axis until the slot 13 exactly crosses the point of intersection of the lower line 22, and the crossing line 23.

The pin 1? is then depressed into the drawing by pressing down on the finger 21, thus holding the instrument firmly in position. Then by moving the block 9 on its straigh edge upwardly to each different division on the chosen scale in turn, and with each such movement placing a pencil through the slot 13 and making a mark on said line 23 as indicated at 24, said line will be very quickly and accurately divided into the desired number of parts or divisions.

It should be noted that the scale chosen for the operation should be the one which will provide the desired number of line divisions with a minimum of angularity of the drum 4 relative to the line to be divided, and While other ones of the scales 8, having a greater number of divisions thereon, but which are necessarily spaced apart a smaller distance, may also be used to obtain the relatively small number of divisions on the line 23, such use disposes the drum at such a large angle to said line as to reduce the likelihood of an easy and accurate dividing of such line. in other words, the smaller the angle between the drum and the line to be divided, the greater 'ill be the accuracy of the dividing operation, with a minimum of manual care.

From th fore oing description it will be readily seen that there has been provided such a line-dividing drafting instrument as will fully fulfill the objects of the invention, as set forth herein.

While this specification sets forth in detail the present and preferred construction of the instrument, still in practice such deviations therefrom maybe resorted to as do not form a'departure from the spirit or" the invention, as defined by the appended claims.

Having thus described the invention, the following is claimed as new and useful, and upon which Letters Patent are desired:

1. A line-dividing drafting instrument comprising end supports spaced apart and adapted to rest on a drawing, a member provided with a longitudinal forwardly facing scale mounted on and extending between the supports, a rigid bar connecting the supports under and clear of the member, a depending pin to penetrate the drawing supported from the bar between the supports, said pin being disposed in front of the member in line with one of the divisions of the scale, a straight-edge projecting at right angles to the scale, and a block rigid with the straight- :r edge and siidably mounted on the bar for movement therealong between the position of the pin and one support and arranged to enable the straight-edge to be alined with any selected division on the scale.

2. An instrument, as in claim 1, in which the front face of the block extends to and registers With the scale, said face having a marker thereon to aline with a division on the scale and said marker being alined with a longitudinal pencil-point receiving slot in the straight-edge.

3. An instrument, as in claim 1, with a friction Wheel mounted on a vertical in the block behind the bar and frictionally engaging the back edge thereof; said wheel projecting from the back face of the block for finger manipulation.

4. An instrument, as in claim 1, with another vertical pin to penetrate the drawing, and means mounting said other pin on one support for selective vertical movement between penetrating and clear positions.

5. An instrument, as in claim 1, in which the member is a rotary drum provid d with a plurality of longitudinally extending differentially divided scales thereon disposed in peripherally spaced relation about the drum.

' 6. An instrument, as in claim 5, with a finger knob connected to the drum outwardly of one support.

References Cited in the file of this patent UNITED STATES PATENTS 397,500 Hoadley Feb. 12, 1889 1,810,392 Clark June 16, 1931 2,242,286 Boughton May 20, 1941 2,331,298 Bennett Oct. 12, 1943 2,370,753 Reece Mar. 6, 1945 2,677,894 Belgard May 11, 1954 2,893,126 Coallier July 7, 1959 

1. A LINE-DIVIDING DRAFTING INSTRUMENT COMPRISING END SUPPORTS SPACED APART AND ADAPTED TO REST ON A DRAWING, A MEMBER PROVIDED WITH A LONGITUDINAL FORWARDLY FACING SCALE MOUNTED ON AND EXTENDING BETWEEN THE SUPPORTS, A RIGID BAR CONNECTING THE SUPPORTS UNDER AND CLEAR OF THE MEMBER, A DEPENDING PIN TO PENETRATE THE DRAWING SUPPORTED FROM THE BAR BETWEEN THE SUPPORTS, SAID PIN BEING DISPOSED IN FRONT OF THE MEMBER IN LINE WITH ONE OF THE DIVISIONS OF THE SCALE, A STRAIGHT-EDGE PROJECTING AT RIGHT ANGLES TO THE SCALE, AND A BLOCK RIGID WITH THE STRAIGHTEDGE AND SLIDABLY MOUNTED ON THE BAR FOR MOVEMENT THEREALONG BETWEEN THE POSITION OF THE PIN AND ONE SUPPORT AND ARRANGED TO ENABLE THE STRAIGHT-EDGE TO BE ALINED WITH ANY SELECTED DIVISION ON THE SCALE. 